<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>id选择器</title>
    <style>
        #pin {
            color: pink;
        }

        /* 一次性的 */
    </style>
</head>

<body>
    <div id="pin">麦克</div>
</body>

</html>